possibility of pregnancy

so in late september i had unprotected sex. it was right at the point where id be ovulating. my period following was a few days early. it was slightly lighter than usual and a day or so less. since then i have had 2 more periods. they have been fairly normal. however, i have gained approximately 10 pounds since then and have had a frequent urge to pee. ive put on weight in my stomach, and breasts. starting a few months prior to this i had a pain begin occuring in my side that they did one test and decided they werent sure what was the cause. i never followed through and stil get this pain. cysts are known to run in the family and i dont know if this would have an effect. i know my my mother had multiple tests turn out negative. even one at the doctor. she didnt find out until 5 months after. well i know its crazy, but i was curious to know if there is a possibility?